By Gifty Anane-Taabeah, a Ph.D. student in fish and wildlife conservation, College of Natural Resources and Environment, and an Interfaces of Global Change Fellow with the Global Change Center at Virginia Tech

[About the blogger: My Ph.D. research focuses on quantifying the genetic variability within and differentiation between natural populations of Nile tilapia Oreochromis niloticus in different river basins in Ghana. We have very little information on the genetic diversity of O. niloticus outside the Volta system. Furthermore, O. niloticus populations in major river basins in Ghana including the Pra, Ankobra, and Tano currently face diverse threats including habitat destruction from illegal small-scale gold mining activities, overfishing, and pollution. Using a population genetics approach, my research seeks to generate baseline data that will aid in conserving the species’ genetic diversity and local adaptation.]

Today is Wednesday June 7, 2017. I am currently lodging in Half-Assini, a border town between Ghana and our western neighboring country, Ivory Coast. I spent most of my day at Elubo, another border town about 45 minutes-drive from Half-Assini, in search of O. niloticus samples. Wednesdays are market days in Elubo and an opportune time to scout for wild-caught O. niloticus. This is especially important because Ghana shares the Tano River with Ivory Coast and the data generated will be useful for conserving the species in both countries.

The Pra River

I have successfully collected samples from the Pra and Ankobra Rivers, and I am amazed about the morphological differences I have observed among individuals within each river. I am already excited about what I will discover after my genetic analysis. I am hopeful that my research will provide the much needed baseline information about O. niloticus genetic diversity in Ghana, and add to the body of knowledge on the population genetics of O. niloticus in West Africa.

My research also seeks to identify wild populations of O. niloticus with a natural local adaptation to future climate conditions in Ghana. The average water temperatures in rivers vary along the latitudinal gradient of Ghana. Our previous experimental studies using different populations from the Volta River basin have revealed that some northern populations of O. niloticus may already be adapted to high temperature conditions, similar to the future climate conditions expected for southern Ghana.

Given this background, I have spent the last four months setting up and running three separate experiments to quantify the adaptation of different wild populations to varying temperature conditions both under laboratory and outdoor conditions, as well as to quantify the heritability of the growth rate trait from parents to their young.

Nile tilapia harvested from the Pra River.

I have a great local team comprising local fishers, government scientists and graduate students who have helped me with the collection of adult fish, monitoring of their growth and reproduction, and selection of their young for the experiments. I am hopeful that the data obtained from this research will be useful in selecting suitable populations and developing them for aquaculture in Ghana and sub-Saharan Africa.